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- #1

- Apr 14, 2013

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Let $X$ be an infinite set and let $x\in X$. Show that there exists a bijection $f:X\to X\setminus \{x\}$. Use, if needed, the axiom of choice.

To show that $f$ is bijective we have to show that it is surjective and injective.

The axiom of choice is equivalent to saying that, the function $f:X\to X\setminus \{x\}$ is surjective if and only if it has a right inverse. So we have to show that the function $f$ has a right inverse, correct?

Next we have to show that the function is injective.

Is that the way we have to proceed for the proof? Or should we do something else?